Method of joining ceramic or graphite to metal with an alloy having high nickel or cobalt content, alloys for joining the same, and products formed therewith

Abstract

A brazed product has a metal substrate, a ceramic or graphite substrate, and a brazing alloy containing one of a high nickel content and cobalt content joining the ceramic or graphite substrate to the metal substrate. A method of joining these materials include providing a metal layer coating of titanium or nickel on the surface of the ceramic or graphite substrate to be joined or using a high nickel content or high cobalt content and containing titanium. The brazing alloy contains a high nickel content 70-95% by weight, or a high cobalt content between 45-55% by weight. This brazing alloy can contain titanium in the range between 0.5-5% by weight.

1. A method of joining first and second components, the first component being composed of metal and the second component being composed of one of ceramic and graphite, the method comprising the steps of
 placing a brazing alloy between surfaces of the first and second components to be joined; and  
 brazing the first and second components with the brazing alloy to join the first and second components together, in at least one of a vacuum atmosphere and an inert atmosphere, with the brazing temperature no greater than about 2200° F.,  
 wherein the brazing alloy contains titanium in the range of 0.5-5 wt % and one of nickel in the range of 70-95 wt % and cobalt in the range of 45-55 wt %, but without aluminum, other than any negligible trace amount.  
 
     
     
       2. A method according to  claim 1 , wherein the brazing alloy is in a form of a tape, foil, or preform. 
     
     
       3. A method according to  claim 1 , further including the step of coating the surface of the second component to be joined with a metal layer. 
     
     
       4. A method according to  claim 3 , wherein the metal layer is composed of one of titanium and nickel. 
     
     
       5. A method according to  claim 1 , wherein the brazing alloy contains 70-95 wt % nickel, and the remainder containing at least one of boron, silicon, phosphorus, chromium, iron, and tungsten. 
     
     
       6. A method according to  claim 1 , wherein the brazing alloy contains 45-55 wt % cobalt, and the remainder containing at least one of boron, silicon, phosphorus, chromium, iron, and tungsten. 
     
     
       7. A method of joining first and second components, the first component being composed of metal and the second component being composed of one of ceramic and graphite, the method comprising the steps of:
 placing a brazing alloy between surfaces of the first and second components to be joined; and  
 brazing the first and second components with the brazing alloy to join the first and second components together,  
 wherein the brazing alloy contains titanium in the range of 0.5-5 wt % and one of nickel in the range of 70-95 wt % and cobalt in the range of 45-55 wt %, and  
 wherein the brazing alloy is composed of the titanium and one of the compositions of AMS4776, AMS4777, AMS4778, AMS4779, AMS4782, AMS4783, and BNi-6.  
 
     
     
       8. A method according to  claim 1 , wherein the second component comprises at least one of alumina, silicon carbide, silicon nitride, single crystal sapphire, and zirconia. 
     
     
       9. A product formed according the method of  claim 1 . 
     
     
       10. A method according to  claim 7 , further including the step of coating the surface of the second component to be joined with a metal layer. 
     
     
       11. A method according to  claim 10 , wherein the metal layer is composed of one of titanium and nickel. 
     
     
       12. A product comprising:
 a metal component; and  
 one of ceramic and graphite components brazed to the metal component with a brazing alloy,  
 wherein the brazing alloy contains titanium in the range of 0.5-5 wt % and one of nickel in the range of 70-95 wt % and cobalt in the range of 45-55 wt %, joining the ceramic or graphite component to the metal component, and  
 wherein the brazing alloy is composed of the titanium and one of the compositions of AMS4776, AMS4777, AMS4778, AMS4779, AMS4782, AMS4793, and BNi-6.  
 
     
     
       13. A product according to  claim 12 , wherein the brazing alloy contains 70-95 wt % nickel, and the remainder containing at least one of boron, silicon, phosphorus, chromium, iron, and tungsten. 
     
     
       14. A product according to  claim 12 , wherein the brazing alloy contains 45-55 wt % cobalt, and the remainder containing at least one of boron, silicon, phosphorus, chromium, iron, and tungsten. 
     
     
       15. A product according to  claim 9 , wherein the ceramic component is brazed to the metal component and comprises at least one of alumina, silicon carbide, silicon nitride, single crystal sapphire, and zirconia. 
     
     
       16. A product according to  claim 9 , wherein the product comprises an engine component. 
     
     
       17. A product according to  claim 16 , wherein the engine component is an inlet guide vane. 
     
     
       18. A product comprising
 a metal component; and  
 one of ceramic and graphite components brazed to the metal component with a brazing alloy,  
 wherein the brazing alloy contains titanium in the range of 0.5-5 wt % and one of nickel in the range of 70-95 wt % and cobalt in the range of 45-55 wt %, joining the ceramic or graphite component to the metal component, and  
 wherein the product comprises a fuel cell.  
 
     
     
       19. A product according to  claim 18 , wherein the ceramic component is composed of yttria stabilized zirconia and the metal component is composed of metal having at least 94.5 wt % chromium. 
     
     
       20. A brazing alloy comprising:
 one of nickel ranging 70-95 wt % and cobalt ranging 45-55 wt %; and  
 titanium ranging 0.5-5 wt %,  
 wherein the brazing alloy is composed of the titanium and one of the compositions of AMS4776, AMS4777, AMS4778, AMS4779, AMS4782, AMS4783, and BNi-6.  
 
     
     
       21. A brazing alloy according to  claim 20 , wherein the brazing alloy is for brazing a metal component to one of ceramic and graphite components. 
     
     
       22. A brazing alloy according to  claim 20 , containing nickel ranging 70-95 wt %, and the remainder containing at least one of boron, silicon, phosphorus, chromium, iron, and tungsten. 
     
     
       23. A brazing alloy according to  claim 20 , containing cobalt ranging 45-55 wt %, and the remainder containing boron, silicon, chromium, nickel, and tungsten. 
     
     
       24. A method according to  claim 4 , wherein the metal layer is composed of essentially pure titanium. 
     
     
       25. A product according to  claim 9 , wherein the product comprises a fuel cell. 
     
     
       26. A product according to  claim 12 , wherein the product comprises an engine component. 
     
     
       27. A product according to  claim 12 , wherein the product comprises a fuel cell.